1. Field of the Invention
The present invention relates, in general, to an optical switch used as essential parts of a wavelength division multiplexing (WDM) optical communications network and, more particularly, to an optical switch, which has a fast response speed, consumes a small amount of an electric power, and is useful in a precise and easy packaging process because it is possible to connect the optical switch to optical fibers according to a simple process, and a method of producing the same.
2. Description of the Related Art
Generally, an optical switch functions to change a path of an optical signal transmitted through an optical fiber in a WDM optical communications network, and current studies of the optical switch are being concentrated on an optical switch realized according to a micro electro mechanical systems (MEMS) technology and an optical switch realized using the refraction change due to heat energy.
In an MEMS optical switch, a beam passing through input optical fibers is reflected by a fine mirror controlled using an actuator having a MEMS structure to be transmitted in two or more directions, and a schematic structure of the MEMS optical switch is illustrated in FIG. 1.
With reference to FIGS. 1A and 1B, the MEMS optical switch includes an input optical fiber 11 through which an optical signal is inputted, a first output optical fiber 12 positioned perpendicular to the input optical fiber 11, a second output optical fiber 13 positioned on the same straight line as the input optical fiber 11, a fine mirror 14 positioned between the input optical fiber 11 and the second output optical fiber 13 and reflecting the optical signal to switch a direction of the optical signal, and an actuator 15 driving the fine mirror 14. When the fine mirror 14 is positioned between the input optical fiber 11 and the second output optical fiber 13 using the actuator 15, the optical signal passing through the input optical fiber 11 is reflected by the fine mirror 14 to advance through the first output optical fiber 12. On the other hand, when the fine mirror 14 is withdrawn from a space between the input optical fiber 11 and the second output optical fiber 13 using the actuator 15, the optical signal passing through the input optical fiber 11 advances through the second output optical fiber 13 without being reflected by the fine mirror 14.
In other words, the optical signal is switched by the fine mirror 14 driven by the actuator 15 having the MEMS structure. Since a size of the actuator is very small, the MEMS optical switch is advantageous in that a switching speed is fast and an electric power is consumed in a small amount. However, the MEMS optical switch has a cumbersome problem in that the input optical fiber and output optical fibers must be precisely arranged in a packaging process.
Referring to FIG. 2, there is illustrated a conventional waveguide optical switch using the refraction change of a waveguide. The conventional waveguide optical switch is structured such that an input waveguide 21, and a first and a second output waveguide 22, 23 are integrated with each other in a Y-shape, the first output waveguide 22 is larger than the second output waveguide 23 in diameter, and a heating unit 24 is attached to the second output waveguide 23. When the heating unit 24 is turned off, an optical signal passing through the input waveguide 21 advances through the first output waveguide 22. On the other hand, when the heating unit 24 is turned on, the second output waveguide 23 is heated by the heating unit 24, thus a refraction ratio is reduced at the second output waveguide 23 and the optical signal passing through the input waveguide 21 advances through the second output waveguide 23, thereby a path of the optical signal is switched.
The conventional waveguide optical switch is advantageous in that waveguide elements are directly mounted on a wafer, thus the integration of waveguide elements is easily conducted, and it is possible to accomplish a packaging process by attaching optical fibers to an input and an output part of the waveguide optical switch without separately arranging the optical fibers. However, the conventional waveguide optical switch has disadvantages in that electric power is consumed in a large amount because heat energy is used to switch the path of the optical signal, and a switching speed is undesirably slow.